I got a good replacement transformer. What I lost on the original wasn't the ground connection; it was one end of the primary. The missing connection was on the inside of the primary coil, about two inches up where the stick is.
Now that I have power, I got all the components cobbled together on the bench; chassis, power supply, speaker, variac, and isolation transformer. All components meet original specs except the three filter condensers which were replaced with .5-, 10-, and 10-uF caps as recommended in an article posted on atwaterkent.info by Ken Owens.
With 110V input, I got good reception and very good audio with NO HUM. BUT...the medium-strength volume was practically unaffected by the volume rheostat and I couldn't receive the signal through my indoor antenna--I had to connect the antenna post to an earth-ground. After quadruple checks on my wiring and disassembling the rheostat I ran the voltage tests, and everything was good except the power tube +B voltage was only157V versus the specified 180V.
So, I reassemble everything in the cabinet, turn it on, and get no sound at all. Quick check shows (Aha!) no filament voltage at the power tube socket (but the voltage is present at the power supply, so that's an easy one, even for me). BUT...now the +B voltage to the power tube is 200V!
So, I disassemble the power supply until I find (Aha!) a broken contact on the speaker choke (also referred to as the plate choke).
So, I repair that and reassemble the power supply and think the problem is solved. BUT...now I have 240V!! +B to the 171A. Further investigation discloses (Aha!) that I have a broken connection to the RF plate circuit resistor.
So, I pull the chassis, repair the broken connections to the plate resistor and the power tube filament voltage and try again. BUT...now the power tube plate voltage is 300V!!! (and the RF plate voltages are high as well). Only the detector seems normal.
I retested all the tubes to make sure that I hadn't killed any of them. I need one more "Aha!" to proceed with the project. Would I be risking damage to the power transformer if ran the set without tubes in? Does anyone know where I might find another "Aha!"?
On the bright side, the refurbished vernier dial works perfectly!
